style.css

* {
    margin: 0;
    padding: 0;
    -moz-user-select:none;
    -webkit-user-select:none;
    -ms-user-select:none;
    -khtml-user-select:none;
      user-select:none;
}


body {
    margin: 0;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}








.fl {
    float: left;
}
button {
    outline: none;
    border: 0;
}
.top-bar {
    height: 40px;
    line-height: 40px;
    background-color: #262626;
    color: #E0E0E0;
    min-width: 540px;

}

/* .top-logo {
    height: 40px;
    width: 128px;
} */



.top-nav{
    min-width: 393px;
    margin-top: 8px;
}
.top-nav button {
    background-color: transparent;
    color: #E0E0E0;
    border-radius: 2px;
    margin-left: 20px;
    padding: 3px 15px;
    float: left;
}

.top-nav button:hover {
    background-color: #A8A8A8;
}
.top-menu-div:hover .top-menu-content{
    display: block;
}

.center-bar {
    background-color: #434343;
    min-width: 1294px;
    height: 38px;
}

.center-group{
    margin: 0;
}

.opt-btn {
    width: 32px;
    height: 32px;
    margin-left: 4px;
    margin-top: 2px;
    background-color: transparent;
    border-radius: 6px;
    background-color: #666666;
    overflow: hidden;
}

.opt-btn:hover {
    background-color: rgba(0, 140, 255, 0.8);
}
.opt-btn:active {
    background-color: #A8A8A8;
}
.opt-btn img {
    margin: 0;
    width: 32px;
    height: 32px;

}



/* Add a black background color to the top navigation */
.topnav {
    background-color: #111;
    overflow: hidden;
  }
  
  /* Style the links inside the navigation bar */
  .topnav a, .topnav label {
    float: left;
    color: #f2f2f2;
    text-align: center;
    padding: 4px 16px;
    text-decoration: none;
    font-size: 14px;
    font-family: Consolas;
  }
  
  /* Change the color of links on hover */
  .topnav a:hover, .topnav label:hover {
    background-color: #aaa;
    color: black;
  }
  
  /* Add a color to the active/current link */
  .topnav a.active, label.active {
    background-color: #4CAF50;
    color: white;
  }